1. Field of the Invention
The present invention relates to a hydraulic tensioner that applies appropriate tension to an endless power transmitting member, such as an endless chain or an endless belt for the power transmission of a valve motion mechanism of an internal combustion engine.
The present invention also relates to leak oil emitting device for a hydraulic tensioner that applies tension to an endless power transmitting member configured from a chain, a belt or the like used in a valve motion of an internal combustion engine.
2. Description of Background Art
An internal combustion engine incorporated in a vehicle such as a motorcycle includes a hydraulic tensioner for pressing an endless power transmitting member, which drives a camshaft of a valve motion mechanism in order to prevent flapping of the endless power transmitting member upon operation of the internal combustion engine.
A hydraulic tensioner is available, wherein a pressure maintaining valve for preventing a pressure drop in a high pressure oil chamber in the hydraulic tensioner in a state in which the oil supplying pressure drops upon stopping of operation of an internal combustion engine is provided in an oil supplying path (refer to, for example, Japanese Patent Laid-Open No. 2009-180359).
An internal combustion engine incorporated in a motorcycle or the like has an endless power transmitting member for driving a cam of a valve motion. In order to prevent flapping of the endless power transmitting member upon operation, the internal combustion engine includes a hydraulic tensioner for pressing the endless power transmitting member. As a conventional example, an example is available wherein the internal pressure of the hydraulic tensioner, which becomes a high pressure, is kept at an appropriate pressure by a gap appearing between a plunger made of a flexible material and a hollow sleeve fitted in the inside of the plunger, and leak oil is emitted from an emitting flow path provided in a housing (refer to, for example, Japanese Patent No. 3594420). However, since the oil entering the gap between an outer face of the plunger and a chamber wall face (plunger accommodating hole) cannot flow out quickly to the outside, movement of the plunger upon forward motion is suppressed, and the follow-up property for a movement of a tensioner slipper is deteriorated. However, if it is tried to carry out accuracy management of the gap over the overall contact area between the plunger outer face and the plunger accommodating hole, then since the accuracy management region is wide, the cost increases.